koreanclass101에서:네, 많이 먹었어요! 찌개중에, 된장찌개가 내 가장 좋아하는 것이다! 너무 너무 맛있고 구수해요!

지금도 먹고 싶어요. 요리 방법을 배우고 싶어요. 정국장을 잊지마세요! 밭처럼 냄새가 있지만 그또 맛있어요.
This is a sentences borrowed from koreanclass101....I was trying to find out what is 정국장...but rather finding a meaningful answer, I found this...then after that I only know that 청국장 is the one 단어 that I am looking for
but why they wrote it as 정국장 instead of 청국장?